The question of “who” or “what” is the Self is the great unanswered question of psychology. Moreover, despite the centrality of the Self to psychology, much of psychology conveniently ignores the Self, focusing instead on mental representations of the Self, affective feelings about the Self, processes deemed to be regulated by the Self, or psychological conditions attributed to health or otherwise of the Self. This strategy is ‘convenient’ both because it allows the Self to be implicated (as it must be) in psychological phenomena of all kinds, whilst at the same time it avoids the hard work of actually defining and describing the Self, often leaving this work to other disciplines.

As a result of the planned ignorance described above, there exists in psychology no agreed definition of the Self and no agreed organizing model(s) of the Self. One key consequence of this lack of agreement is that psychology has become a fragmented discipline, spawning various schools of psychology each with its own sub-fields of research nested within separate, non-articulated philosophical, theoretical, conceptual and empirical frameworks. Moreover, with each successive generation of scholars, these frameworks become more complex, sometimes more convoluted, and typically more inaccessible to scholars working with and within other frameworks.

In contrast to previous approaches, in this paper we propose a specific definition and model of the Self –and one that transcends classical psychological conceptions of the Self. This transcendence occurs by adopting a transdisciplinary psychophenomenological approach, which incorporates first-person perspectives from philosophical inquiry, and combines these perspectives with a model-based approach that is common in psychology and which forms the basis of psychometric modeling and empirical investigation. Specifically, the model combines key psychological constructs such as self-consciousness and self-concept, with key phenomenological entities such as the Knowing I and the Reflective Self, showing how these constructs and entities interact and interrelate within the self-system to form the substance of experience, perception and cognition.

The model represents a theory-driven account of the Self that is congruent with, corresponds to, complements, and extends existent plain language and scientific accounts of the Self in an insightful, integrated and thoughtfully structured manner. In so doing, the model seeks to develop an integrated and integrating understanding of the I-Self that may be utilized across the fragmented field of psychology and in other disciplines as well. In particular, we suggest that the model may be utilized in a variety or research settings and contexts where systematic, parsimonious and insightful descriptions and analyses of the Self form the focus, or the basis, of investigations.